The present invention relates to a treatment equipment of exhaust gas containing organic halogen compounds. In more detail, it relates to an equipment for introducing exhaust gas containing organic halogen compounds into a catalytic decomposition unit to decompose and then removing hydrogen halide decomposition product of the organic halogen compounds in a wash tower.
The organic halogen compounds are utilized in various fields not only a raw material of chemical substances, but also as washing agents etc. At that time, exhaust gas containing organic halogen compounds is emitted. Some of these organic halogen compounds include compounds having toxicities such as carcinogenicity etc., source substances of air pollution and further compounds having been considered as source substances of ozonosphere destruction and greenhouse effect being problems in the global enviroment, consequently, the development of the technology to suppress the emission has been promoted.
As a treatment equipment of exhaust gas containing organic halogen compounds, an adsorption recovery method is conventionally known. Using an adsorption recovery method, however, the treatment of organic halogen compounds recovered becomes problematic. While direct recycling is possible in the case of the purity of recovered material being high, usually impurities are most often incorporated that makes it necessary to purify by distillation before recycling. Moreover, among the recovered materials, those incapable of recycling are required to be treated as waste liquors leading to a problem of cost.
Besides the adsorption recovery method, direct combustion method is also considered to be a treatment method. The direct combustion method however requires a temperature of higher than 800.degree. C. and a temperature of higher than 1000.degree. C. becomes necessary depending on the kind of organic halogen compounds. Moreover, since the direct combustion method is performed at high temperature, thermal NOx is generated and further there is a possibility dioxin is produced resulting in a cause of new pollution problems.
As described above, the treatment method of exhaust gas containing organic halogen compounds has problems in the post-treatment and has also a danger of becoming a cause of new pollution problems, hence the development of more effective treatment equipment of exhaust gas containing organic halogen compounds is desired.
As a result of investigations on the treatment method of exhaust gas containing organic halogen compound, the inventors have succeeded in effectively treating an exhaust gas containing organic halogen compounds at low temperature by introducing the exhaust gas into a catalytic decomposition unit after concentrating the organic halogen compounds in a concentration unit when the organic halogen compounds is at a low concentration or is directly introduced when at high concentration and then hydrogen halide is removed in a wash tower.